Objective: To describe the impact of a parent-led, family-focused child weight management program on the food intake and activity patterns of pre-pubertal children. Methods: An assessor-blinded, randomized controlled trial involving 111 (64% female) overweight, pre-pubertal children 6–9 years of age randomly assigned to parenting-skills training plus intensive diet and activity education (P + DA), parenting-skills training alone (P), or a 12-month wait-listed control (WLC). Study outcomes were assessed at baseline, 6 months, and 12 months. This paper presents data on food intake assessed via a validated 54-item parent-completed dietary questionnaire and activity behaviours assessed via a parent-report 20-item activity questionnaire. Results: Intake of energy-dense nutrient-poor foods was lower in both intervention groups at 6 months (mean difference, P + DA − 1.5 serves [CI − 2.0; −1.0]; P − 1.0 serves [−2.0; −0.5]) and 12 months (mean difference P + DA − 1.0 serves [CI − 2.0; −0.5]; P − 1.0 serves [− 1.5; 0.0]) compared to baseline. Intake of vegetables, fruit, breads and cereals, meat and alternatives and dairy foods remained unchanged. Regardless of study group there were significant reductions over time in the reported time spent engaged in small screen activities and an increase in the time reported spent in active play. Conclusion: A child weight management intervention that promotes food intake in line with national dietary guidelines achieves a reduction in children's intake of energy-dense, nutrient-poor foods. This was achieved without compromising intake of nutrient-rich food and changes were maintained even once the intervention ceased.